The invention relates to a method of manufacturing a device having a part which comprises a wall having a first surface and an oppositely located second surface, said part being subjected to a temperature treatment in which said part is heated by irradiation with heat via the first surface by means of heat radiators.
The invention further relates to a heater for carrying out the method.
The invention also relates to a display device having a part which comprises a wall and which is treated in accordance with said method.
Such a method is used in the manufacture of camera tubes, image amplifiers, oscilloscopes, lamps and, in particular, cathode ray tubes (CRTs) for displaying monochromatic images or color images. Such a method is also used in the manufacture of thin-type display devices in vacuum tubes, plasma displays and plasma-addressed liquid-crystal display devices (PALC displays).
A method of the type mentioned in the opening paragraph is known from United States Patent U.S. Pat. No. 4,498,884 (PHN 9.980). In said document, a description is given of a method which relates to the manufacture of a display device comprising a display screen with a raised edge and a cone, the display screen and the cone being subjected to a temperature treatment in a furnace. To reduce the stresses occurring in the display screen, measures are taken to minimize differences in thermal expansion between the outermost and innermost surfaces of the display device during the warm-up part of the temperature treatment. According to these measures, a heat shield is provided on or at some distance from (the central part) of the display screen, said heat shield being provided with a pattern of apertures.
A disadvantage of the known method is that a (patterned) heat shield is a complicated construction and therefore less suitable for use in mass-production processes. In addition, for every type of display screen, which each have a different size (dimensions) and thickness, other heat shields must be constructed and tested, and the heat shields must be exchanged if, in the manufacturing process, a changeover from one type of display screen to another type of display screen is effected.